Claude Code Mods

Claude Code Mods let developers change the behavior and interface of Claude Code using JavaScript or TypeScript event handlers. Anthropic announced the feature on October 1, 2026. A mod ships inside a plugin, so existing plugin installation and distribution workflows apply. This is useful when a reusable instruction alone cannot implement the interaction you need.

Key features

A handler can observe an event, change it before execution, or handle it instead of the built-in behavior. Examples in the official documentation include rewriting a prompt, guarding tool calls, adding a command, and sharing state between handlers. Mods can draw interactive panes, buttons, and fields, or change parts of the existing interface. Some built-in features, including the diff interface, have public mod implementations.

Mods require Claude Code v2.1.287 or later. The terminal CLI and the Code tab of the desktop app display mod interfaces, with documented exceptions. Hooks can run in other supported sessions without displaying the custom UI. Do not assume the VS Code chat panel renders a mod's panes.

A practical starting workflow

Read the official overview and its create-a-mod tutorial. Begin with a tool-call counter that observes events and shows a count. Check your version with claude --version, then inspect the plugin's files and run claude plugin validate ./some-mod before installing code from a trusted source. The validator lists handled events and requested API calls; it does not establish that arbitrary code is safe.

After installing or updating a mod from the shell, use /reload-plugins in an existing session. Open /plugin to check what loaded. Test the intended event with a small task, then disable the plugin if it changes behavior unexpectedly. A useful first team project is a visible CI status panel, rather than automatic approval of sensitive operations.

Pricing and limitations

Mods are part of Claude Code's plugin system. This listing does not establish a separate mod price; Claude Code plan or API usage still applies, and a mod can call a model and consume usage.

Mods run with your permissions and are not sandboxed. They can read files and secrets, make network requests, and change session behavior. Organization plugin controls and managed settings apply; the official announcement describes a security-default mod for managed environments. Review the current documentation before deploying a policy across a team.

FAQ and alternatives

How are mods different from skills? Skills supply instructions in Markdown. Mods execute event handlers and can draw an interface.

When is MCP preferable? Use MCP when the requirement is to expose an external service as tools. A plugin can contain both.

What should I use first? Claude Code is the host product. Claude.dev provides the first-mod tutorial. GitHub Copilot is another coding-assistant option, not a compatible mod runtime.

Browse development tools for adjacent products. Start with an observation-only mod, validate its calls, and review the result before adding behavior-changing handlers.